In some parts of the US, police kill black people at a rate six times higher than they kill white people. The differences are most stark in the northern Midwest, especially Chicago, and in north-eastern states like New York.
Protest movements like Black Lives Matter have highlighted the disproportionate killing of black people by US police, and called for major changes in policing practices. However, official data on police killings can be unreliable. The database run by the Bureau of Justice Statistics is known to undercount deaths, partly because police forces don’t have to contribute data. That makes it harder to stop the killings.
Gabriel Schwartz and Jaquelyn Jahn at Harvard University compared police killings in different regions of the US between 2013 and 2017. They used data from Fatal Encounters, an independent organisation that gathers public and media reports of killings, and fact-checks them.
The researchers assigned each death to one of the US’s 382 “metropolitan statistical areas”. These are “cities and the areas surrounding cities”, says Jahn, and reflect where people spend most of their time